Question

If f(x)=4(3x-5), find f^-1(x)

Answer 1

f^-1(x) = (x+20) / 12

Explanation:

f(x) = 4(3x-5)

Let y be the image of f.

y = 4(3x-5)

y = 12x-20

y+20 = 12x

x = (y+20) / 12

f^-1(y) = (y+20) / 12, so

f^-1(x) = (x+20) / 12